When buying my setup I was given free goldfish flakes, Nutrafin Max to be exact. I have purchased some TetraMin tropical fish food aswel but I am just wondering if there is any difference other than the colour? Can I feed my tropical fish with these goldfish flakes?

I try and vary the diet of my fish. While I personally wouldn't buy gold fish flakes, I don't think there would be anything wrong with feeding them to them once or twice a week. Free food is free food. I don't THINK there is any difference between them , other than goldfish flakes have a higher spirullena alga content.